Semiconductor wafer handling robots are very specialized types of robot that typically include one or two robot arms that terminate in an end effector that may be used to lift a semiconductor wafer. Such robots are used to transport semiconductor wafers in between locations in a semiconductor processing tool, and may operate in either vacuum or atmospheric environments. Such arms typically primarily move in the horizontal plane, although they may also be equipped with a Z-axis linear drive to allow for the entire arm assembly to be moved vertically; they typically do not include the ability to rotate about axes other than vertical axes (no pitch/roll, only yaw).